Boot upper



FIG. 1 is a perspective view of a boot upper;

FIG. 2 is a left view of the boot upper;

FIG. 3 is a right view of the boot upper;

FIG. 4 is rear view of the boot upper;

FIG. 5 is a front view of the boot upper;

FIG. 6 is a top view of the boot upper; and,

FIG. 7 is a bottom view of the boot upper. 

I claim the ornamental design for a boot upper, as shown and described. 